Operating rod for self-loading firearm



April 19, 1966 A. MILLER 3,246,567

OPERATING ROD FOR SELF-LOADING FIREARM Filed June 15, 1964 United StatesPatent 3,246,567 OPERATING ROD FOR SELF-LOADING FIREARM Arthur Miller,Costa Mesa, Calif., assignor to Armaiite, Inc., Costa Mesa, Calif., acorporation of California Filed June 15, 1964, Ser. No. 375,256 Claims.(Cl. 89-191) This invention relates to an improvement in theconventional gas-actuated push rod system for a self-loading firearm,more particularly, to a push rod system particularly adapted to alightweight, self-loading firearm of the rapid fire type.

In the conventional gas-actuated push rod system for a self-loadingfirearm, the gas is bled from a port in the barrel into a piston andcylinder arrangement.

It is preferred in the interest of less weight to locate the gas port onthe barrel nearer the muzzle where the gas pressure is less and theunlocking and reloading can be effected with less massive mechanism thanis required for storing the kinetic energy to effect reloading with ashort-coupled gas system. However, a long and relatively rigid push rodis required in such a system. The rigid push rod is attached to thepiston cylinder arrangement on one end and the other end is attached tothe receiver mechanism in a manner to actuate the selfloading mechanism.It is spring-biased for the return stroke.

If the push rod is of reduced diameter to eliminate weight, it will bendor whip by reason of the rapid action of the firearm and in theconventional system, introduces binding or galling in the piston andcylinder assembly. The binding or galling of the piston and cylinderwill cause malfunction or greatly reduce the effectiveness of thesystem.

In the present invention, the push rod can be of greatly reduceddiameter from the conventional push rod and designed to bend freelywithin the elastic limits of the material without impairing the functionof the weapon and thus effecting a considerable reduction in the weightof the push rod. This is accomplished by the mounting of the push rod onthe piston assembly as hereinafter described.

It is an object of this invention to provide a lightweight push rod fora gas-actuated push rod system through the reduction of the diameter ofthe push rod which can bend freely in operation Without impairing theoperation of the system or causing malfunction of the system.

It is another object of this invention to provide a mounting for a pushrod for gas-actuated push rod system for a self-loading firearm thatwill bend freely without transmitting the bending of the push rod to thepiston cylinder assembly.

Further and other objects of this invention will become apparent fromthe description of the accompanying drawings in which like numeralsrefer to like parts.

In the drawings:

FIG. 1 is a fragmentary view of a rapid self-loading firearmgas-actuated push rod system;

FIG. 2 is a fragmentary view of the forward end of the barrel of thesystem, showing the push rod assembly in the operating position;

FIGS. 3 and 4 are views of an alternate arrangement of the push rodpiston cylinder assembly on a rifle barrel.

FIGURE 1 of the drawing shows a rifle barrel 1 secured to a receiver 2.Block 3 represents a portion of the self-loading system which isactuated by push rod 4. Push rod 4 extends into the receiver 2 and movesblock 3, as the rifle is fired, for reloading.

On the forward end of barrel 1, gas is bled off at port 5 in the barreland through passage 6. Piston 7 has passage 8 formed therein and it isthreaded at 9 into bracket 10 which is rigidly secured to barrel 1. Acylinder 11 surrounds piston 7 and moves rearwardly of the barrel witheach firing.

The forward end of push rod 4 is formed with a spherical surfaceengaging a similar spherical surface on cylinder 11. The forward end ofpush rod 4 and the rearward end of cylinder 11 have inter-engagingmeans, such as pin 13 loosely fitting in hole 14, to provide freedom ofmovement of push rod 4 with respect to cylinder 11 at surface 12. Spring15 biases push rod 4 against cylinder 11 throughout the operation of thesystem.

When the rifle is fired and the bullet passes port 5, a small quantityof gas under high pressure is bled off through passages 6 and 8 andcauses cylinder 11 to move rearwardly of the barrel of the rifie. Themotion of cylinder 11 is transmitted to push rod 4, and in turn, to boltunlocking and reloading mechanism represented at 3.

If rapid fire causes push rod 4 to bend or whip, the forward end willmerely move with respect to cylinder 11 on spherical surface 12, and nobending or stress will occur between cylinder 11 and piston 7 that willtend to gall and produce malfunction.

As shown in FIG. 2, relative motion of piston 7 and cylinder 11 will becoaxial.

FIGS. 3 and 4 show the same result with a lightweight push rod, but withthe connection of the piston and cylinder reversed. Piston 7' has formedon its rearward end, spherical surface 12 and projection 13. Cylinder111 is threaded to engage bracket 10. The remainder of the partsfunction in the manner described in connection with FIGS. 1 and 2.

A long, lightweight push rod is thus achieved which will operatereliably over a long period of time and achieve the overall feature ofsaving in weight in the self-loading system including the unlocking andreloading mechanism.

It is to be undertsood that certain changes, alternations, modificationsand substitutions can be made without departing from the spirit andscope of the appended claims.

What is claimed is:

1. A lightweight push rod system for a self-loading firearm comprising abarrel, a gas port formed therein near the muzzle end of said barrel, apiston and cylinder assembly secured to said barrel, means forming apassage to interconnect said piston and cylinder assembly and said gasport to conduct gas from said barrel to actuate said piston and cylinderassembly, said piston and cylinder assembly formed with a spherical endsurface perpendicular to the axis of said assembly, a push rodinterconnecting said piston and cylinder assembly and the self-loadingmechanism of the firearm, said push rod having the end adjacent saidpiston and cylinder assembly formed with a mating spherical surface,loosely coupled locator means positioning said spherical end of saidpush rod on said spherical end of said piston and cylinder assembly andbiasing means to hold said spherical surfaces in contact and to permitrelative motion of said push rod along said barrel, but out of axialalignment with said piston and cylinder assembly, said locator meanscomprising an elongated pin on one of said spherical surfaces, looselyengaging a longer hole formed in the other of said spherical surfaces.

2. The device as set forth in claim 1, in which said means forming apassage interconnecting said piston and cylinder assembly and said gasport is a bracket firmly secured to said barrel, said piston andcylinder assembly being mounted on said bracket.

.3. The device as set forth in claim 1, in which said bracket is a frontsight bracket.

3 4. The device as set forth in claim 1, in which the pis- ReferencesCited by the Examiner ton of said piston and cylinder assembly ismounted on UNITED STATES PATENTS said bracket with the axis thereofextending generally aranel to the axis of said barrel 564,043 7/1896Benet et al 89-191 X P 5 Th d f h 1 h h 5 1,524,974 2/1925 Hazelton s9193 e evlce as Set on In C alnl 1 W t 5 3 0 9 97 1 2 Stevens 89-191cylinder of said piston and cylinder assembly is mounted Y I on saidbracket with the axis thereof extending generally BENJAMIN BORCFIELTExammer' parallel to the axis of said barrel. FRED C. MATTERN, In,Examiner.

1. A LIGHTWEIGHT PUSH ROD SYSTEM FOR A SELF-LOADING FIREARM COMPRISING ABARREL, A GAS PORT FORMED THEREIN NEAR THE MUZZLE END OF SAID BARREL, APISTON AND CYLINDER ASSEMBLY SECURED TO SAID BARREL, MEANS FORMING APASSAGE TO INTERCONNECT SAID PISTON AND CYLINDER ASSEMBLY AND SAID GASPORT TO CONDUCT GAS FROM SAID BARREL TO ACTUATE SAID PISTON AND CYLINDERASSEMBLY, SAID PISTON AND CYLINDER ASSEMBLY FORMED WITH A SPHERICAL ENDSURFACE PERPENDICULAR TO THE AXIS OF SAID ASSEMBLY, A PUSH RODINTERCONNECTING SAID PISTON AND CYLINDER ASSEMBLY AND THE SELF-LOADINGMECHANISM OF THE FIREARM, SAID PUSH ROD HAVING THE END ADJACENT SAIDPISTON AND CYLINDER ASSEMBLY FORMED WITH A MATING SPHERICAL SURFACE,LOOSELY COUPLED LOCATOR MEANS POSITIONING SAID SPHERICAL END OF SAIDPUSH ROD ON SAID SPHERICAL END OF SAID PISTON AND CYLINDER ASSEMBLY ANDBIASING MEANS TO HOLD SAID SPHERICAL SURFACES IN CONTACT AND TO PERMITRELATIVE MOTION OF SAID PUSH ROD ALONG SAID BARREL, BUT OUT OF AXIALALIGNMENT WITH SAID PISTON AND CYLINDER ASSEMBLY, SAID LOCATOR MEANSCOMPRISING AN ELONGATED PIN ON ONE OF SAID SPHERICAL SURFACES, LOOSELYENGAGING A LONGER HOLE FORMED IN THE OTHER OF SAID SPHERICAL SURFACES.